U.S. Pat. No. 4,754,247 entitled "Molded Case Circuit Breaker Accessory Enclosure" describes a so-called "integrated" circuit breaker that provides both circuit interruption as well as accessory function. This Patent is incorporated herein for reference purposes and should be reviewed for its disclosure of an accessory cover mounted on the circuit breaker cover for providing access to field-installable accessory devices. The integrated circuit breaker includes anintegrated circuit electronic trip unit which allows one circuit breaker design to be used over a wide range of ampere ratings in combination with a rating plug, also mounted in the circuit breaker cover. The electronic trip unit is described within U.S. Pat. No. 4,589,052 and the rating plug is described within U.S. Pat. No. 4,649,455 both of which are incorporated herein for reference purposes.
The use of common circuit breaker components over a wide variety of ampere ratings could provide a strain on the circuit breaker case in the vicinity of the line and load terminal straps upon short circuit interruption when operated at high ampere loadings. The large electrodynamic forces exerted between adjacent line terminal straps and between adjacent load terminal straps exert corresponding large stress forces to the underlying case to which the line and load terminal straps are secured.
One purpose of the instant invention accordingly is to provide a reinforced circuit breaker case to enable an integrated circuit breaker to respond to high ampere short circuit overcurrent conditions without damaging the circuit breaker case.